The present invention relates to an apparatus for preventing reverse rotation of an engine, particularly to the apparatus for stopping the engine by escaping compression pressure when its rotation reverses upon starting.
When a diesel engine having a high compression ratio, it is hard to crank manually to exceed a top dead center, so that reverse rotation may occur because of ignition prior to reaching the top dead center, and consequently the engine will continue to rotate in the reverse direction.
Various apparatus for preventing the reverse rotation of the engine have been proposed to stop an engine when it continues to rotate in the reverse direction because of this.
For example, in Japanese Utility Model Laid-Open Publication No. 176452/1980 is disclosed an apparatus for preventing reverse rotation of an engine wherein, in an engine which is rotating in reverse, a cam protrudes due to the centrifugal force produced by that rotation and a cam follower interconnected with this cam operates a fuel pump control rack to forcedly move the fuel pump to a fuel cut position.
However, in such an apparatus for preventing reverse rotation of an engine of the prior art, the cam that protrudes due to centrifugal force is used to perform the cutting-off of the fuel, and so when the engine is stopped from reverse rotation, the speed of the engine drops. The centrifugal force becomes progressively weaker, and the abovementioned cam no longer protrudes and as a consequence, the fuel is no longer cut off. Therefore, the engine starts to rotate in reverse once again from a slow speed.
Moreover, it is also necessary to separately provide a link mechanism to interconnect the cam follower and the control rack of the fuel pump. This makes the structure more complex and also complicates the assembly procedure, and increases the product cost as a consequence.